Subject: Heavy swapping causes deadlock in uvm_unlock_fpageq
To: None <>
From: Rick Byers <>
List: current-users
Date: 07/05/2001 09:07:11
I just started doing more memory intensive stuff (i.e. lots of swapping)
on my NetBSD-1.5.1/i386 machine, and have been having problems with it
hanging.  I can still switch virtual consoles and break into the debugger,
but nothing else works.  Here is the stack trace:
uvm_unlock_fpageq (+0x13)

So it looks like there is some sort of deadlock in the paging code.  I
left top running this last time and when it froze top wasn't indicating
that swap space was almost exhausted or anything (infact I think it said
100 Mb free) - although there were about 6 perl processes running.

Anyway, so my question is - I haven't noticed anything like this on my
NetBSD-current/i386 machine (although it probably doesn't do as much
swapping), does anyone know of anything that may have been fixed in
-current but not -release that could cause this?

My -release is built from June 26 sources - I'm updating now just in case.
I've got a crash dump, so if there is anything I can do to help track this
down - let me know.  It's happened twice now in the last 12 hours, so I'm
sure it'll happen again...